CVE-2025-2026
📋 TL;DR
This vulnerability allows authenticated remote attackers with web read-only privileges to execute null byte injection through the NPort device's web API. This can cause the device to reboot unexpectedly, resulting in a denial-of-service condition. Organizations using NPort 6100-G2/6200-G2 series devices are affected.
💻 Affected Systems
- NPort 6100-G2 Series
- NPort 6200-G2 Series
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Persistent attacker causes repeated device reboots, creating extended service disruption and potential data loss from interrupted communications.
Likely Case
Temporary denial of service from device reboot, disrupting serial-to-Ethernet communications until device restarts.
If Mitigated
Minimal impact with proper network segmentation and access controls limiting exposure.
🎯 Exploit Status
Requires authenticated access but only read-only privileges needed; null byte injection is a well-understood attack vector.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific firmware versions
Restart Required: Yes
Instructions:
1. Download latest firmware from Moxa support site. 2. Backup device configuration. 3. Upload firmware via web interface. 4. Apply firmware update. 5. Reboot device. 6. Restore configuration if needed.
🔧 Temporary Workarounds
Disable Web Interface
allDisable the web management interface if not required for operations
Configure via serial console or disable in web interface settings
Network Segmentation
allRestrict access to device management interfaces to trusted networks only
Configure firewall rules to block external access to device web ports
🧯 If You Can't Patch
- Implement strict network access controls to limit device management interface exposure
- Monitor device logs for reboot events and suspicious API requests
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against vendor advisory; test if null byte injection in web API causes device rebootCheck Version:
Check via web interface System Information page or serial consoleVerify Fix Applied:
Verify firmware version is updated to patched version; test that null byte injection no longer causes device reboot📡 Detection & Monitoring
Log Indicators:
- Unexpected device reboots
- Web API requests containing null bytes
- Authentication logs from read-only accounts
Network Indicators:
- HTTP requests to device web API with encoded null bytes
- Increased reboot-related network traffic
SIEM Query:
source="nport" AND (event="reboot" OR uri="*%00*")